A WCDMA system is composed of the following network elements: User Equipment (UE), an UMTS Terrestrial Radio Access Network (UTRAN) and a Core Network (CN). The UTRAN is responsible for functions relevant to wireless side processing. The CN is responsible for performing voice and data exchange with an external network.
A macro diversity function of the WCDMA is directly relevant to soft handover. When UE is in an inter-cell handover state, the UE may need to communicate with a plurality of base stations (Node b) participating in handover at the same time, and combine signals sent from these base stations so as to improve the signal quality of uplink and downlink to ensure not to lose data in the handover process. This technology is referred to as macro diversity which enables communications not to be affected when the UE is moving.
Generally, under a condition of macro diversity, the same data packet sent by the UE is sent to a radio network controller (Radio Network Control, referred to as RNC) respectively passing two or more base stations. The RNC is responsible for determining the handover of the UE, completing data combining, and sending the signal to a core network.
In the specific implementation of the RNC performing macro diversity combining, various information in an uplink FP (Frame Protocol) data frame would be received together with a data block, then it is judged when storing the data that if FP frames with the same connection frame number (Connection Frame Number, referred to as CFN) are existed, then combining processing is performed. The data blocks with a correct cyclic redundancy check indicator (Cyclic Redundancy Check Indicator, referred to as CRCI) are put to corresponding positions. If none of the data blocks have correct CRCI, then data blocks with small quality estimate values (Quality Estimate QE) are put to the corresponding positions. When a medium access control (Medium Access Control, referred to as MAC) layer is performing uplink scheduling, data contents of FP frames are acquired according to an ascending order of the CFN, and are put to corresponding logical channels after demultiplexing and decryption.
However, since Iub transmission path distances and service load conditions of different stations are different, a time delay difference inevitably exists in a macro diversity state when data of various links arrives at the RNC. However, when a MAC is performing uplink scheduling, all data of all links needs to be completely collected for a certain CFN point before further processing can be performed, and this introduces the concept of macro diversity combining waiting time.
If the data of all links are not completely collected when a preset waiting time of macro diversity combining expires after data of a first link arrives, then it is judged that the waiting of macro diversity combining times out, and at this time subsequent processing may be performed on combined data of other links. However, in practical applications, in one aspect, in order to collect all the data of all links, waiting time of macro diversity combining theoretically needs to be configured to be large enough; while in the other aspect, in order to improve data processing performance, the waiting time of macro diversity combining also needs to be configured to be relatively small. In order to solve this problem, a method for dynamically adjusting the waiting time of uplink macro diversity combining is urgently needed, so that during the operation, a system can automatically select a suitable waiting time of macro diversity combining to effectively improve the performance of the system.